Methods of field preservation and selection of sample tissue for condensed tannin analysis in Leucaena species

Field sample preservation and tissue selection for condensed tannin (CT) analysis were investigated with three Leucaena genotypes, L. leucocephala subspecies glabrata (Lam.) de Wit cv. Tarramba (K636), L. pallida Britton and Rose (K806) and the F1 interspecific hybrid L. pallida (K748) × L. leucocephala (K636). Shoot, youngest fully expanded leaf (YFEL) and mature leaf (ML) tissues were analysed for extractable, protein and fibre-bound CT for each Leucaena species. There was no significant difference in CT content measured in excised tissues whether frozen by dry ice or liquid nitrogen. The shoot material of all genotypes contained more CT, of all components, than the YFEL and ML tissues. Extractable CT was highest in L. pallida, lowest in L. leucocephala and intermediate in the hybrid. The YFEL was selected as the most appropriate sample tissue because it was easily recognized, enabled consistent sampling of tissue at the same physiological stage of maturity, and contained sufficient CT for the determination of the CT status of each genotype.